Previously, indication of the temperature of an infant feeding container, particularly a baby bottle, has been by touch or feel of the outside of the bottle or by shaking a few drops on ones arm in a temperature sensitive area. Since the advent of thermochromatic compositions, the addition of paint containing this substance has been used by prior art applied to the outside of the container for temperature indication. Other approaches utilize a binary mixture of cholesteric liquid crystals of various colors yielding a visual array of color related directly to the container temperature.
A search of the prior art did not disclose any patents that read directly on the claims of the instant invention, however, the following U.S. Patents were considered related:
______________________________________ U.S. Pat. No. Inventor Issue Date ______________________________________ 4,620,941 Yoshikawa et al Nov. 4, 1986 4,538,926 Chretien Sep. 3, 1985 4,424,990 White et al Jan. 10, 1984 4,228,761 Glover et al Oct. 21, 1980 4,156,365 Heinmets et al May 29, 1979 3,864,976 Parker Feb. 11, 1975 ______________________________________
Chretien in U.S. Pat. No. 4,538,926 teaches a bottle with a thin supple support with a black background and an axially located binary mixture of cholesteric liquid crystals and a colored strip from red to violet with a mark on the appropriate color. The mating color of the strip to the crystals indicates the desire temperature. It will be noted that this combination is placed entirely on the surface of the container.
Glover et al utilize a heat-deformable polymeric material coated with a thermochromic paint containing a thermochromic pigment having a metallic compound. The improvement includes inhibiting degradation by the addition of a combination of non-thermochromatic compounds.
Heinmets et al discloses a vessel having a layer of thermochromic paint positioned at a location visible to the user. The temperature is indicated by a set of dots contiguous with a background of color reference and indica indicating the represented temperatures.
Parker employs a digital thermometer strip having a thin dimensionally stable plastic film with a mask leaving alpha-numeric symbols transparent. Liquid crystal compositions with transition temperatures related to the designation are coated onto the mask with the strip introduced between the films of waterpermeable plastic. The plastic exchanges the heat from the bottle upon which the strip is mounted indicating the temperature visually by the transparent or opaque nature of the crystal composition.
For background purposes and as indicative of the art to which the invention relates, reference may be made to the remaining cited patents issued to Yoshikawa et al and White et al.